1. Field of the Invention:
The present invention relates generally to a flow rate control device for recirculating the exhaust gas to be purified within an internal combustion engine, and more specifically to a digital control device for controlling the flow rate of the recirculated exhaust gas.
2. Description of the Prior Art:
Device for recirculating a portion of the exhaust gas from an internal combustion engine and for purifying the same have of course been in wide-spread use for some time. Apparatus equipped with a valve, controllable to open or close in response to the negative pressure within the suction or intake tube, is typical of such devices, within this device, the specified valve-opening characteristic cannot be altered as the occasion requires.